As Iran and the 5+1 “big powers” prepare for a new round of nuclear negotiations, Tehran is attracting new support from unexpected quarters in Washington.

The lobbyist-in-chief is President Obama who, in his State of the Union Address, presented a rosy picture of the talks and threatened to veto new sanctions that Congress might pass. Endorsing Obama’s stance, Sens. Carl Levin and Angus King penned a New York Times op-ed, “Don’t Undermine the Iran Deal.” In a rare sortie, former Secretary of State Hillary Clinton wrote Levin endorsing his opposition to further sanctions.

Yet this position is based on a series of false premises.

The first of these comes at the start of the Levin-King op-ed: “There are only two ways to keep Iran from developing a nuclear weapon: negotiations or military action.”

This is bound to appeal to a war-weary public, yet the claim that these are the only two options is false. The Levin-King duo admits this by stating that “sanctions that have been imposed on Iran over the last three decades have worked.”

There are only two examples of trying to persuade a nation to abandon its nuclear project through negotiations: North Korea and Iran, with no success in either case. There has been one case of stopping a nation’s nuclear ambitions through war, that of Iraq in 1991 — but even then, what clinched the deal in the end was regime change in 2003.

Regime change has worked in other cases. Argentina dropped its nuclear program after the toppling of the military regime. In South Africa, the collapse of the Apartheid regime produced the same result. In others cases, notably Ukraine and Kazakhstan, regime change after the collapse of the Soviet Empire spelled the end of nuclear arsenals. In Libya, a mixture of sanctions and “proximity pressure” forced Moammar Khadafy to abandon his nuclear project (which evenually produced regime change as well).

The second false premise of the Obama-Levin-King-Clinton analysis is that Hassan Rouhani, the new president of the Islamic Republic, is a “moderate” who ought to be supported against hardline rivals. In fact, nothing in Rouhani’s record or his performance as president reveals him as moderate in any reasonable sense of that much-abused term.

Rouhani is one of the founding members of the security and intelligence services (VAVAJI) created by Ayatollah Khomeini to crush opponents. As a security official, Rouhani ran the Khatem al-Anbia Co., which supervises infrastructure projects for the Revolutionary Guard.

For years, Rouhani worked as secretary-general of the High Council on National Security. In that capacity under President Mohammed Khatami, he orchestrated the crushing of student revolts and led a nationwide campaign to wipe out independent trade unions. The so-called “chain murders” that claimed the lives of some 80 intellectuals and political activists during Khatami’s presidency came when Rouhani was in charge of national security.

And what has Rouhani done as president?

He formed an administration studded with security officers, including individuals who took part in holding US diplomats hostage in 1979-80. (One hostage-holder is vice president; another is minister of defense.) And President Rouhani is now holding three US hostages, including a former FBI agent.

Last Sunday, Rouhani addressed a gathering of security officers in Tehran to demand “a more resolute campaign against the enemies of revolution.” He described the secret service as “the backbone of our system.”

Since the “moderate” Rouhani was elected, between 320 and 430 people (including at least 29 women) have been executed, according to different estimates. This execution spree takes Iran back to the dark days of the 1990s when an average of 10 people were put to death daily.

UN Special Envoy Christof Heyns urged Iran last month to stop the surge in executions. “It is deeply concerning that the government proceeds with executions for crimes that do not meet the threshold of the ‘most serious crimes’ as required by international law and when serious concerns remain about due-process rights,” said Heyns.

“Moderate” Rouhani has also ordered the arrests of scores of independent trade-union members. The permits of more than 20 publications have been canceled and 14 editors have been arrested.

The third false premise in the Obama-Levin-King-Clinton analysis is that a “deal” has been reached with Iran. In fact, Iranian officials from Rouhani on down keep repeating that nothing has been signed. According to Ali-Akbar Salehi, the man in charge of Iran’s nuclear project, that program will not change “by a single iota.”

Deputy Foreign Minister Abbas Araqchi says the Geneva “accord” was nothing but a statement of steps “the two sides decided to take voluntarily.” Even then, it is not clear what those steps are. Araqchi says “implementation modalities” are contained in a 66-page ­“non-paper” that no one, not even the parliaments of the nations concerned, have seen.

The Levin-King duo says: “Don’t Undermine the Iran Deal.” But could they tell the American people what the deal is?